sw_sync.c revision 45acea57335ece628bdf96dc35d2ebdefd1efb9e 
1/*
2 * drivers/base/sw_sync.c
3 *
4 * Copyright (C) 2012 Google, Inc.
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 */
16
17#include <linux/kernel.h>
18#include <linux/export.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/miscdevice.h>
22#include <linux/module.h>
23#include <linux/syscalls.h>
24#include <linux/uaccess.h>
25
26#include "sw_sync.h"
27
28static int sw_sync_cmp(u32 a, u32 b)
29{
30	if (a == b)
31		return 0;
32
33	return ((s32)a - (s32)b) < 0 ? -1 : 1;
34}
35
36struct sync_pt *sw_sync_pt_create(struct sw_sync_timeline *obj, u32 value)
37{
38	struct sw_sync_pt *pt;
39
40	pt = (struct sw_sync_pt *)
41		sync_pt_create(&obj->obj, sizeof(struct sw_sync_pt));
42
43	pt->value = value;
44
45	return (struct sync_pt *)pt;
46}
47EXPORT_SYMBOL(sw_sync_pt_create);
48
49static struct sync_pt *sw_sync_pt_dup(struct sync_pt *sync_pt)
50{
51	struct sw_sync_pt *pt = (struct sw_sync_pt *) sync_pt;
52	struct sw_sync_timeline *obj =
53		(struct sw_sync_timeline *)sync_pt->parent;
54
55	return (struct sync_pt *) sw_sync_pt_create(obj, pt->value);
56}
57
58static int sw_sync_pt_has_signaled(struct sync_pt *sync_pt)
59{
60	struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
61	struct sw_sync_timeline *obj =
62		(struct sw_sync_timeline *)sync_pt->parent;
63
64	return sw_sync_cmp(obj->value, pt->value) >= 0;
65}
66
67static int sw_sync_pt_compare(struct sync_pt *a, struct sync_pt *b)
68{
69	struct sw_sync_pt *pt_a = (struct sw_sync_pt *)a;
70	struct sw_sync_pt *pt_b = (struct sw_sync_pt *)b;
71
72	return sw_sync_cmp(pt_a->value, pt_b->value);
73}
74
75static int sw_sync_fill_driver_data(struct sync_pt *sync_pt,
76				    void *data, int size)
77{
78	struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
79
80	if (size < sizeof(pt->value))
81		return -ENOMEM;
82
83	memcpy(data, &pt->value, sizeof(pt->value));
84
85	return sizeof(pt->value);
86}
87
88static void sw_sync_timeline_value_str(struct sync_timeline *sync_timeline,
89				       char *str, int size)
90{
91	struct sw_sync_timeline *timeline =
92		(struct sw_sync_timeline *)sync_timeline;
93	snprintf(str, size, "%d", timeline->value);
94}
95
96static void sw_sync_pt_value_str(struct sync_pt *sync_pt,
97				       char *str, int size)
98{
99	struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
100	snprintf(str, size, "%d", pt->value);
101}
102
103static struct sync_timeline_ops sw_sync_timeline_ops = {
104	.driver_name = "sw_sync",
105	.dup = sw_sync_pt_dup,
106	.has_signaled = sw_sync_pt_has_signaled,
107	.compare = sw_sync_pt_compare,
108	.fill_driver_data = sw_sync_fill_driver_data,
109	.timeline_value_str = sw_sync_timeline_value_str,
110	.pt_value_str = sw_sync_pt_value_str,
111};
112
113
114struct sw_sync_timeline *sw_sync_timeline_create(const char *name)
115{
116	struct sw_sync_timeline *obj = (struct sw_sync_timeline *)
117		sync_timeline_create(&sw_sync_timeline_ops,
118				     sizeof(struct sw_sync_timeline),
119				     name);
120
121	return obj;
122}
123EXPORT_SYMBOL(sw_sync_timeline_create);
124
125void sw_sync_timeline_inc(struct sw_sync_timeline *obj, u32 inc)
126{
127	obj->value += inc;
128
129	sync_timeline_signal(&obj->obj);
130}
131EXPORT_SYMBOL(sw_sync_timeline_inc);
132
133#ifdef CONFIG_SW_SYNC_USER
134/* *WARNING*
135 *
136 * improper use of this can result in deadlocking kernel drivers from userspace.
137 */
138
139/* opening sw_sync create a new sync obj */
140static int sw_sync_open(struct inode *inode, struct file *file)
141{
142	struct sw_sync_timeline *obj;
143	char task_comm[TASK_COMM_LEN];
144
145	get_task_comm(task_comm, current);
146
147	obj = sw_sync_timeline_create(task_comm);
148	if (obj == NULL)
149		return -ENOMEM;
150
151	file->private_data = obj;
152
153	return 0;
154}
155
156static int sw_sync_release(struct inode *inode, struct file *file)
157{
158	struct sw_sync_timeline *obj = file->private_data;
159	sync_timeline_destroy(&obj->obj);
160	return 0;
161}
162
163static long sw_sync_ioctl_create_fence(struct sw_sync_timeline *obj,
164				       unsigned long arg)
165{
166	int fd = get_unused_fd_flags(O_CLOEXEC);
167	int err;
168	struct sync_pt *pt;
169	struct sync_fence *fence;
170	struct sw_sync_create_fence_data data;
171
172	if (fd < 0)
173		return fd;
174
175	if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
176		err = -EFAULT;
177		goto err;
178	}
179
180	pt = sw_sync_pt_create(obj, data.value);
181	if (pt == NULL) {
182		err = -ENOMEM;
183		goto err;
184	}
185
186	data.name[sizeof(data.name) - 1] = '\0';
187	fence = sync_fence_create(data.name, pt);
188	if (fence == NULL) {
189		sync_pt_free(pt);
190		err = -ENOMEM;
191		goto err;
192	}
193
194	data.fence = fd;
195	if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
196		sync_fence_put(fence);
197		err = -EFAULT;
198		goto err;
199	}
200
201	sync_fence_install(fence, fd);
202
203	return 0;
204
205err:
206	put_unused_fd(fd);
207	return err;
208}
209
210static long sw_sync_ioctl_inc(struct sw_sync_timeline *obj, unsigned long arg)
211{
212	u32 value;
213
214	if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
215		return -EFAULT;
216
217	sw_sync_timeline_inc(obj, value);
218
219	return 0;
220}
221
222static long sw_sync_ioctl(struct file *file, unsigned int cmd,
223			  unsigned long arg)
224{
225	struct sw_sync_timeline *obj = file->private_data;
226
227	switch (cmd) {
228	case SW_SYNC_IOC_CREATE_FENCE:
229		return sw_sync_ioctl_create_fence(obj, arg);
230
231	case SW_SYNC_IOC_INC:
232		return sw_sync_ioctl_inc(obj, arg);
233
234	default:
235		return -ENOTTY;
236	}
237}
238
239static const struct file_operations sw_sync_fops = {
240	.owner = THIS_MODULE,
241	.open = sw_sync_open,
242	.release = sw_sync_release,
243	.unlocked_ioctl = sw_sync_ioctl,
244	.compat_ioctl = sw_sync_ioctl,
245};
246
247static struct miscdevice sw_sync_dev = {
248	.minor	= MISC_DYNAMIC_MINOR,
249	.name	= "sw_sync",
250	.fops	= &sw_sync_fops,
251};
252
253static int __init sw_sync_device_init(void)
254{
255	return misc_register(&sw_sync_dev);
256}
257
258static void __exit sw_sync_device_remove(void)
259{
260	misc_deregister(&sw_sync_dev);
261}
262
263module_init(sw_sync_device_init);
264module_exit(sw_sync_device_remove);
265
266#endif /* CONFIG_SW_SYNC_USER */
267